I added one variation to this strategy. Select Dazzling Dance [2] as the third skill on your Frolicker. The second enemy pet, Rawly, usually does Burrow as his second attack, and then uses Powerball, which increases his speed. He got fast enough that he got an extra attack off on my Frolicker, which meant the final pet killed it.

So when Rawly does Burrow (and you can't hit him anyway), use Dazzling Dance. Then go back to the Barkskin/Bite rotation.

Four attempts and none of them even came close. Ended up using backline pets to finish the last pet which isn't really any trouble but the strategy posted here makes it sound like the Frolicker can reliably solo the fight which is not true.